In late May, The Faraday Institute hosted a pair of lectures on evolution by experts in their fields. On 24 May, Prof. Elliott Sober (University of Wisconsin-Madison), one of the leading philosophers of biology in the world today, spoke on ‘Naturalism and Evolutionary Theory’. According to current evolutionary theory, much of the variety we see in nature – including the things that make you and me unique – is generated by random, unguided changes in DNA, or “mutations”.

This description may not sit comfortably with a theistic believer who understands God to be intimately and actively involved with His creation. However, Sober argued that evolutionary theory does not necessarily rule out the idea that God could guide mutations. Sober pointed out that when biologists refer to mutations as ‘unguided’, they do not mean that mutations have no cause. And whilst we know of some physical processes that cause mutations, we certainly don’t have any assurance that we know all of them. Sober likened this to tossing a coin: we know the probability of getting heads or tails but when the coin lands on heads, we don’t know all the causes of this event – our explanation is causally incomplete. He said that if you are an evidentialist – someone who thinks that you can only believe what we have evidence for – then you should be agnostic about whether God guides mutation. If you reject evidentialism, then you are of course free to believe that God guides mutations, or, conversely, that mutations are definitely not guided by a God.

Evolutionary theory cannot tell you whether to be an evidentialist or not. So, if you adopt a non-agnostic position, it is important to realise that you are doing this on the basis of a philosophy, not on the basis of evolutionary theory itself. A few days later, on 28 May, a lecture on ‘The Evolution of Cooperation’ was given by Martin Nowak, Professor of Biology and Mathematics at Harvard University. Beginning with an analysis of the Prisoner’s Dilemma, a classic topic in game theory, he went on to show how the interplay of strategies of cooperation and defection works out in more realistic situations. Hence he was able to show how behaviours such as forgiveness and direct and indirect reciprocity would give a pay off. Direct reciprocity is of the ‘you scratch my back, I’ll scratch yours variety’, whereas indirect reciprocity is the receipt of a benefit from an individual other than the one the recipient has helped. The latter is based on reputation and it is what has made us human, because it requires language. Nowak quoted David Haig’s pithy way of putting it: ‘For direct reciprocity you need a face. For indirect reciprocity you need a name.’ Nowak said that no non-human animals have the ability of naming. Nowak claims that the old idea of kin selection (behaviour which helps relatives) is flawed and that standard natural selection is a superior approach for interpreting empirical observations. T

hose who wish to read more about Martin Nowak’s viewpoint may find a popular version in an article by him in the current edition of Scientific American. [Photo: Faraday Director Dr Denis Alexander (left) with Prof. Elliott Sober (right)]

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